Near-total darkness and water depths below 200 m define the deep sea, Earth’s largest yet most poorly studied ecosystem. Sowerby’s beaked whales (Mesoplodon bidens), elusive deep-sea foragers, offer a unique opportunity to assess the impacts of anthropogenic pollutants in this remote environment. This study examined a range of legacy and emerging hydrophobic pollutants, including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), and polychlorinated alkanes (PCAs), across tissues from five stranded whales foraging in Swedish waters. Despite global efforts to reduce pollution, significant pollutant levels in these whales underscore the persistence of legacy contaminants and the widespread use of PCAs. Most pollutants were concentrated in lipid-rich blubber, while PCAs exhibited particularly high levels in whole blood (941-13100 ng/g lipid), indicating tissue-specific accumulation. Blubber pollutant levels were similar to those of harbor porpoises from the same waters, with p,p′-DDE (1020-2280 ng/g lipid) and PCBs (1230-1930 ng/g lipid) exceeding or nearing effect thresholds. Blood concentrations of legacy pollutants were approximately an order of magnitude higher than those in humans from the region, while PCA levels were comparable to those of humans. These findings highlight the urgent need to investigate deep-sea exposure pathways and develop effective management strategies.

Children are exposed to endocrine disrupting chemicals (EDCs) through inhalation and ingestion, as well as through dermal contact in their everyday indoor environments. The dermal loadings of EDCs may contribute significantly to children's total EDC exposure due to dermal absorption as well as hand-to-mouth behaviors. The aim of this study was to measure potential EDCs, specifically halogenated flame retardants (HFRs) and organophosphate esters (OPEs), on children's hands during preschool attendance and to assess possible determinants of exposure in preschool indoor environments in Sweden. For this, 115 handwipe samples were collected in winter and spring from 60 participating children (arithmetic mean age 4.5 years, standard deviation 1.0) and analyzed for 50 compounds. Out of these, 31 compounds were identified in the majority of samples. Levels were generally several orders of magnitude higher for OPEs than HFRs, and 2-ethylhexyl diphenyl phosphate (EHDPP) and tris(2-butoxyethyl) phosphate (TBOEP) were detected in the highest median masses, 61 and 56 ng/wipe, respectively. Of the HFRs, bis(2-ethyl-1-hexyl)-2,3,4,5-tetrabromobenzoate (BEH-TEBP) and 2,2′,3,3′,4,4′,5,5′,6,6′-decabromodiphenyl ether (BDE-209) were detected in the highest median masses, 2.8 and 1.8 ng/wipe, respectively. HFR and/or OPE levels were found to be affected by the number of plastic toys, and electrical and electronic devices, season, municipality, as well as building and/or renovation before/after 2004. Yet, the calculated health risks for single compounds were below available reference dose values for exposure through dermal uptake as well as for ingestion using mean hand-to-mouth contact rate. However, assuming a high hand-to-mouth contact rate, at the 95th percentile, the calculated hazard quotient was above 1 for the maximum handwipe mass of TBOEP found in this study, suggesting a risk of negative health effects. Furthermore, considering additive effects from similar compounds, the results of this study indicate potential concern if additional exposure from other routes is as high.

Polar regions should be given greater consideration with respect to the monitoring, risk assessment, and management of potentially harmful chemicals, consistent with requirements of the precautionary principle. Protecting the vulnerable polar environments requires (i) raising political and public awareness and (ii) restricting and preventing global emissions of harmful chemicals at their sources. The Berlin Statement is the outcome of an international workshop with representatives of the European Commission, the Arctic Council, the Antarctic Treaty Consultative Meeting, the Stockholm Convention on Persistent Organic Pollutants (POPs), environmental specimen banks, and data centers, as well as scientists from various international research institutions. The statement addresses urgent chemical pollution issues in the polar regions and provides recommendations for improving screening, monitoring, risk assessment, research cooperation, and open data sharing to provide environmental policy makers and chemicals management decision-makers with relevant and reliable contaminant data to better protect the polar environments. The consensus reached at the workshop can be summarized in just two words: “Act now!”

Specifically, “Act now!” to reduce the presence and impact of anthropogenic chemical pollution in polar regions by.

•Establishing participatory co-development frameworks in a permanent multi-disciplinary platform for Arctic-Antarctic collaborations and establishing exchanges between the Arctic Monitoring and Assessment Program (AMAP) of the Arctic Council and the Antarctic Monitoring and Assessment Program (AnMAP) of the Scientific Committee on Antarctic Research (SCAR) to increase the visibility and exchange of contaminant data and to support the development of harmonized monitoring programs.

•Integrating environmental specimen banking, innovative screening approaches and archiving systems, to provide opportunities for improved assessment of contaminants to protect polar regions.

The large number and diversity of organohalogen compounds(OHCs)occurring in the environment poses a grand challenge to analyticalchemists. Since no single targeted method can identify and quantifyall OHCs, the size of the OHC iceberg may be underestimated.We sought to address this problem in municipal wastewater treatmentplant (WWTP) sludge by quantifying the unidentified fraction of theOHC iceberg using targeted analyses of major OHCs together with measurementsof total and extractable (organo)halogen (TX and EOX, respectively;where X = F, Cl, or Br). In addition to extensive method validationvia spike/recovery and combustion efficiency experiments, TX and/orEOX were determined in reference materials (BCR-461 and NIST SRMs2585 and 2781) for the first time. Application of the method to WWTPsludge revealed that chlorinated paraffins (CPs) accounted for most(similar to 92%) of the EOCl, while brominated flame retardants and per-and polyfluoroalkyl substances (PFAS) accounted for only 54% of theEOBr and 2% of the EOF, respectively. Moreover, unidentified EOF innonpolar CP extracts points to the existence of organofluorine(s)with physical-chemical properties unlike those of target PFAS.This study represents the first multihalogen mass balance in WWTPsludge and offers a novel approach to prioritization of sample extractsfor follow-up investigation. A multihalogenmass balance experiment in WWTP sludge revealedhigh levels of unidentified organofluorine and organobromine. Organochlorinewas characterized mainly by chlorinated paraffins.

This study analysed settled dust samples in Sweden to assess children's combined exposure to 39 organohalogenated flame retardants (HFRs) and 11 organophosphate esters (OPEs) from homes and preschools. >94 % of the targeted compounds were present in dust, indicating widespread use of HFRs and OPEs in Swedish homes and preschools. Dust ingestion was the primary exposure pathway for most analytes, except BDE-209 and DBDPE, where dermal contact was predominant. Children's estimated intakes of ∑_emerging HFRs and ∑_legacy HFRs from homes were 1–4 times higher than from preschools, highlighting higher exposure risk for HFRs in homes compared to preschools. In a worst-case scenario, intakes of tris(2-butoxyethyl) phosphate (TBOEP) were 6 and 94 times lower than the reference dose for children in Sweden, indicating a potential concern if exposure from other routes like inhalation and diet is as high. The study also found significant positive correlations between dust concentrations of some PBDEs and emerging HFRs and the total number of foam mattresses and beds/m², the number of foam-containing sofas/m², and the number of TVs/m² in the microenvironment, indicating these products as the main source of those compounds. Additionally, younger preschool building ages were found to be linked to higher ΣOPE concentrations in preschool dust, suggesting higher ΣOPE exposure. The comparison with earlier Swedish studies indicates decreasing dust concentrations for some banned and restricted legacy HFRs and OPEs but increasing trends for several emerging HFRs and several unrestricted OPEs. Therefore, the study concludes that emerging HFRs and OPEs are replacing legacy HFRs in products and building materials in homes and preschools, possibly leading to increased exposure of children.

Fluorine mass balance studies have shown that monomeric per- and polyfluoroalkyl substances (PFAS) with perfluoroalkyl chain lengths of ∼5–14 carbon atoms (i.e., “conventional” PFAS) account for a fraction (∼2%) of the extractable organic fluorine (EOF) in municipal wastewater treatment plant (WWTP) sludge. The identity of the remaining EOF has thus far been unclear but may be partly attributable to fluorine-containing pharmaceuticals and pesticides used throughout society. To test this hypothesis, we applied high resolution mass spectrometry-based suspect screening to samples of municipal WWTP sludge which had been previously subjected to a fluorine mass balance. Sixteen pharmaceutical substances (including transformation products [TPs]), one pesticide, and thirteen conventional PFAS were confirmed at confidence levels 1–4 and (semi)quantified, revealing concentrations ranging from 0.07 to 155 ng/g dw. Notably, eight pharmaceutical substances did not meet the OECD definition of PFAS. When converted to fluorine equivalents, the newly detected organofluorine substances increased the percentage of known EOF from ∼2% to ∼27%, of which ∼22% was attributed to pharmaceutical and pesticide substances, with the greatest contributions from ticagrelor TP (4.0%), ezetimibe (3.9%), and bicalutamide (3.5%). These data highlight the importance of considering both unconventional and non-PFAS organofluorine substances in addition to conventional PFAS when closing the organofluorine mass balance in WWTP sludge.

Determining the major human exposure pathways is a prerequisite for the development of effective management strategies for environmental pollutants such as chlorinated paraffins (CPs). As a first step, the internal and external exposure to CPs were quantified for a well-defined human cohort. CPs in participants’ plasma and diet samples were analyzed in the present study, and previous results on paired air, dust, and hand wipe samples were used for the total exposure assessment. Both one compartment pharmacokinetic modeling and forensic fingerprinting indicate that dietary intake contributed the most to body burden of CPs in this cohort, contributing a median of 60–88% of the total daily intakes. The contribution from dust ingestion and dermal exposure was greater for the intake of long-chain CPs (LCCPs) than short-chain CPs (SCCPs), while the contribution from inhalation was greater for the intake of SCCPs than medium-chain CPs (MCCPs) and LCCPs. Significantly higher concentrations of SCCPs and MCCPs were observed in diets containing butter and eggs, respectively (p < 0.05). Additionally, other exposure sources were correlated to plasma levels of CPs, including residence construction parameters such as the construction year (p < 0.05). This human exposure to CPs is not a local case. From a global perspective, there are major knowledge gaps in biomonitoring and exposure data for CPs from regions other than China and European countries.

Germany is one of several major European producers of chlorinated paraffins (CPs). This study showed that not only the legacy short-chain products (SCCPs, C10-13), but also the current-use medium- and long-chain products (MCCPs, C14-17; LCCPs, C 17) as well as the very-short-chain impurities (vSCCPs, C<10) are ubiquitous in the 72 samples collected from the coastal, terrestrial, and freshwater ecosystems across the country. The concentrations of LCCPs surpassed those of the other CPs in 40% of the biota samples. Archived bream samples collected downstream of a CP-manufacturing factory showed decreasing temporal trends of (v)SCCPs and relatively constant levels of MCCPs from 1995 to 2019; however, the overall levels of LCCPs have increased by 290%, reflecting the impact of chemical regulation policies on changes in CP production. A visualization algorithm was developed for integrating CP results from various matrices to illustrate spatial tendencies of CP pollution. Higher levels of (v)SCCPs were indicated in the former West Germany region, while MCCP and LCCP concentrations did not seem to differ between former East and West Germany, suggesting relatively equal production and use of these chemicals after the German Reunification. The results provide an early warning signal of environmental concerns from LCCPs on the eve of their booming global production and use.

Persistent organic pollutants (POPs) have accumulated in polar environments as a result of long-range transport from urban/industrial and agricultural source regions in the mid-latitudes. Climate change has been recognized as a factor capable of influencing POP levels and trends in the Arctic, but little empirical data have been available previously. A growing number of recent studies have now addressed the consequences of climate change for the fate of Arctic contaminants, as reviewed and assessed by the Arctic Monitoring and Assessment Programme (AMAP). For example, correlations between POP temporal trends in air or biota and climate indices, such as the North Atlantic Oscillation Index, have been found. Besides the climate indices, temperature, precipitation and sea-ice were identified as important climate parameters influencing POP levels in the Arctic environment. However, the physical changes are interlinked with complex ecological changes, including new species habitats and predator/prey relationships, resulting in a vast diversity of processes directly or indirectly affecting levels and trends of POPs. The reviews in this themed issue illustrate that the complexity of physical, chemical, and biological processes, and the rapid developments with regard to both climate change and chemical contamination, require greater interdisciplinary scientific exchange and collaboration. While some climate and biological parameters have been linked to POP levels in the Arctic, mechanisms underlying these correlations are usually not understood and need more work. Going forward there is a need for a stronger collaborative approach to understanding these processes due to high uncertainties and the incremental process of increasing knowledge of these chemicals. There is also a need to support and encourage community-based studies and the co-production of knowledge, including the utilization of Indigenous Knowledge, for interpreting trends of POPs in light of climate change.

Time series of contaminants in the Arctic are an important instrument to detect emerging issues and to monitor the effectiveness of chemicals regulation, based on the assumption of a direct reflection of changes in primary emissions. Climate change has the potential to influence these time trends, through direct physical and chemical processes and/or changes in ecosystems. This study was part of an assessment of the Arctic Monitoring and Assessment Programme (AMAP), analysing potential links between changes in climate-related physical and biological variables and time trends of persistent organic pollutants (POPs) in Arctic biota, with some additional information from the Antarctic. Several correlative relationships were identified between POP temporal trends in freshwater and marine biota and physical climate parameters such as oscillation indices, sea-ice coverage, temperature and precipitation, although the mechanisms behind these observations remain poorly understood. Biological data indicate changes in the diet and trophic level of some species, especially seabirds and polar bears, with consequences for their POP exposure. Studies from the Antarctic highlight increased POP availability after iceberg calving. Including physical and/or biological parameters in the POP time trend analysis has led to small deviations in some declining trends, but did generally not change the overall direction of the trend. In addition, regional and temporary perturbations occurred. Effects on POP time trends appear to have been more pronounced in recent years and to show time lags, suggesting that climate-related effects on the long time series might be gaining importance.